1. Field of the Invention
The present invention relates to fluoroscopy apparatus.
This application is based on Japanese Patent Application No. 2009-072848, the content of which is incorporated herein by reference.
2. Description of Related Art
It has hitherto been known that in fluoroscopy apparatus such as fluorescence endoscopes, the irradiation intensity of excitation light in the observation region varies depending on the angle and distance of the excitation light with which the observation target is irradiated, and the intensity of fluorescence generated varies. In order to correct such variation in the fluorescence intensity, fluoroscopy apparatus is known in which the effect of distance and angle is corrected by performing division by a reference image acquired in the same observation region (e.g., a reflected-light image or the like) (e.g., see Japanese Unexamined Patent Application, Publication No. Sho 62-247232).
Furthermore, a method is known in which the resolution is intentionally reduced by low-pass filtering an image acquired as a reference image (e.g., see Japanese Unexamined Patent Application, Publication No. 2001-224549).
However, the reference image includes information other than information about the distance and angle, for example, image information of blood vessel structures or edges in a case where the observation target is biological tissue. Therefore, if correction is performed by simply using the reference image, in some cases, it is not possible to perform quantitative correction over the entire image, which results in degraded image quality.
Furthermore, in a case where it is necessary to perform image processing for removing high-frequency components on all the pixels of the acquired image information, the processing speed becomes slow.